The algae feed on phosphorous — and that phosphorous comes from fertilizers and detergents that wash down driveways and lawns, onto streets and finally into streams and creeks.

Frobisher Creek is the creek that Bradley said is pumping a lot of the pollutants into Ramsey, particularly when it rains.

In total, "there was over 400 mg of phosphorous per second estimated to be going into Ramsey Lake," she said. "That is a lot of phosphorous."

That's five times higher than provincial standards.

'Change the bad behaviour'

Bradley said Frobisher Creek is a hotspot because of all the neighbourhoods built around it.

World-renowned ecologist David Schindler, who recently visited Sudbury to speak with a group of citizens concerned with the blue-green algae outbreaks, said cities need to stop turning forests and wetlands into subdivisions and parking lots.

"We just have to change the bad behavior," he said. "We don't really need much in the way of additional science any more."

The area Frobisher Creek runs through is being targeted by developers who are planning to put in hundreds of more homes in the coming years.

In the meantime, Bradley said "Frobisher Creek should be at least continually monitored … and possibly have some sort of storm water containment area or something along those lines."

Currently in the works is a city bylaw banning phosporous fertilizers. That will help, Bradley said, but she noted it could be decades before Ramsey Lake is back to normal.